The present invention generally relates to a system and a method for using dual telemetry for tools located in a wellbore. More specifically, the present invention relates to a first telemetry system and a second telemetry system that may coordinate communication with the tools. The first telemetry system and the second telemetry system may be used to transmit data regarding the tools, wellbore, formation, drillstring or wellbore conditions from the wellbore to a surface location. The first telemetry system and the second telemetry system may communicate with the surface location if communication using the other telemetry system is interrupted.
To obtain hydrocarbons, a drilling tool is driven into the ground surface to create a borehole through which the hydrocarbons are extracted. Typically, a drill string is suspended within the borehole. The drill string has a drill bit at a lower end of the drill string. The drill string extends from the surface to the drill bit. The drill string has a bottom hole assembly (BHA) located proximate to the drill bit.
Drilling operations typically require monitoring to determine the trajectory of the borehole. Measurements of drilling conditions, such as, for example, drift of the drill bit, inclination and azimuth, may be necessary for determination of the trajectory of the borehole, especially for directional drilling.
The BHA may have tools that may generate and/or may obtain information regarding the wellbore, a formation surrounding the wellbore and drilling conditions. Technology for transmitting information within a wellbore, known as telemetry technology, is used to transmit the information from the tools of the BHA to the surface for analysis. The information may be used to control the tools. Accurate real-time information regarding the tools, the wellbore, the formation and the drilling conditions may enable prevention and/or detection of a drilling problem, such as, for example, a hazard region which the drilling tool must avoid, a blowout, casing wear and/or the like. Moreover, adjustment of the drilling operations in response to accurate real-time information may enable optimization of the drilling process to increase a rate of penetration of the drill bit, reduce a drilling time and/or optimize a placement of the wellbore.
Drilling fluid, such as, for example, mud, may be pumped through a conduit in the drill string. The drilling fluid may be used to transmit the information regarding the drilling tool and the drilling conditions to the surface location. For example, the flow of the mud through the drill string may be modulated to cause pressure and/or flow rate variations proximate to the surface location as known to one skilled in the art as “mud-pulse telemetry.”
Wired drill pipe, such as the wired drill pipe infrastructure described in U.S. Pat. No. 6,641,434, enables high-speed transmission of the information from the tools to the surface location. The wired drill pipe infrastructure may have communication cables embedded in the drill pipe for transmittal of the information. In addition, the communication cables may be connected to coupling devices located at each joint of the drill pipe to enable transmission of the information and transmission of the drilling fluid through the drill pipe.
The wired drill pipe enables high-speed transmission of the information from the sensors to the surface location. The high-speed transmission by the wired drill pipe may provide a data transmission rate that may be orders of magnitude greater then a data transmission rate of other telemetry technologies, such as, for example, mud pulse telemetry or electronic pulse telemetry. The high-speed transmission by the wired drill pipe may also provide data transmission from relatively distant drilling depths. However, the communication channel provided by the wired drill pipe may be interrupted, such as, for example, if adjacent joints of the wired drill pipe are separated. Therefore, use of both mud pulse telemetry and wired drill pipe telemetry may be advantageous.
However, use of both mud pulse telemetry and wired drill pipe telemetry may be difficult because each telemetry system may attempt to request data from and/or control a tool simultaneously. Communication between a tool and a wired drill pipe telemetry system may interfere with communication between a tool and a mud pulse telemetry system.